Ogre and GEV were both published , originaly, by Metagaming Concepts in 1977 - 1978; they were Metagame 1 and Metagame 8. When Steve Jackson split from Metagaming to form Steve Jackson Games he took Ogre and GEV with him. Though they have gone through several printings they remain basicaly the same. The expansion pack Shockwave adds more maps and unit types to the mix. There is an Ogre book due to be out 1st Qtr '01 that includes many of the fan made mods, scenerios, maps and variants.